Anti-Cyclic Citrullinated Peptide (anti-CCP) test for Rheumatoid Arthritis

Anti-Cyclic Citrullinated Peptide (CCP) testing will be performed in the Immunopathology Laboratory as of January 27, 2005.  The same "second-generation" test reagents and methodology will be used as are currently employed by the reference laboratory to which this test has previously been sent.  The normal/reference range will be unchanged.
Anti-CCP has been shown in multiple studies to be a more specific serum test for rheumatoid arthritis than rheumatoid factor (RF).  The test becomes positive earlier in the course of rheumatoid arthritis than RF and is less commonly found to be positive in other autoimmune connective tissue diseases such as systemic lupus erythematosus.  Unlike RF, it is seldom positive in patients with infectious diseases or in normal elderly individuals.  The overall sensitivity of "second generation" anti-CCP tests for rheumatoid arthritis is about 75-80% while the specificity is 91% in patients with other rheumatic diseases, 98% in patients with infectious diseases, and 99% in otherwise healthy patients.  In contrast, the overall sensitivity of IgM RF (the commonly available RF test) is about 70% and the overall specificity is about 80-85%.  It is expected that a positive anti-CCP will be added to the American College of Rheumatology diagnostic criteria for RA fairly soon.
Test specimen required:  Serum (1 ml minimum)
Normal (reference) range:  < 20 units
Testing offered once per week, excluding weekends and University holidays.
Comments should be directed to John D. Kemp, MD, (4-9611), Michael Icardi, MD, (4-8632), Sergei Syrbu, MD, PhD, (6-7372), James Goeken, MD, (6-1966), or Lisa Horning, MT (ASCP), SI, (6-2846).